The present invention provides a low cost system and method for receiving and storing raster scan video signals in a bit-mapped computer graphics system. The preferred embodiment was designed to be added to low cost personal computer systems having bit-mapped graphics capability. Other embodiments of the invention could be designed for use with virtually any bit-mapped graphics system.
The preferred embodiment allows the user to view a video picture on the monitor of a personal computer, to adjust the contrast of the picture, to adjust the coloring of the picture, and to store a selected picture or image for later use. The stored picture can then be modified or added to using graphics software of the type which is already widely used on personal computer systems.
A feature of the present invention is the use of a relatively simple sequential process for storing a raster scan video signal which avoids the need to simultaneously process all of the information in the video signal. In particular, a preselected portion of the video information, such as one fifth of the relevant information, can be processed during each raster scan cycle. This feature allows significant reductions in the cost of the system by reducing the speed and complexity of the circuitry used.
Another feature of the present invention is that the bit-mapped image generated by the system is stored using a cyclic encoding technique which reduces or minimizes "digitization jitter"--the tendency of the image to noticeably fluctuate, especially along the boundaries of objects and along other color and brightness boundaries.
It is therefore a primary object of the present invention to provide a system and method for receiving and storing video images in a bit-mapped computer graphics system.
Other objects of the present invention include the provision of a low cost system having the above described features, and the minimization of digitization jitter.